Safety device for presses and the



Jan. 30, 1934. w MACHE 1,945,116

SAFETY DEVICE FOR PRESSES AND THE LIKE Filed Aug. 6, 1930 2 Sheets-Sheet l W wwofivai mo n @W 'bw W YW Jan. 30, 1934. w. MACFIE SAFETY DEVICE FOR PRESSES AND THE LIKE Filed Aug. 6, 1930 2 Sheets-Sheet 2 Patented Jan. 30, 1934 UNITED STATES PATENT OFFICE.

William Leslie Macfie, London,

England, as-

signor to Andrew & Suter Limited, London, England, a British Company Application August 6, 1930, Serial No. 473,505, and in Great Britain June 20, 1930 6 Claims.

This invention relates to safety devices for presses, punching machines, box staying machines and the like and has more particular reference to safety devices for rendering the positive actuation of the movable pressure member, die or punch of the machine inoperative should obstruction of its movement occur by reason for example of the machine attendants fingers being in the way.

The object of the present invention is to provide an improved and simplified form of safety device and according to the invention a suitably arranged locking element such as a key or keys or their equivalent are adapted to be moved into a position to lock the movable die or punch for positive operation only when it is within a predetermined distance of a stationary die or anvil said key or keys being prevented from moving into the operative position should premature obstruction of the movable die or punch occur. The said key or keys are rotatably mounted in a reciprocating slide which is adapted to be locked to an actuating member or block to cause positive operation of the movable pressure member, die or punch carried by said slide. Preferably two keys are provided and each carries bell crank levers the movements of which are controlled by means of cams mounted upon a fixed part of the machine, the bell crank levers and said keys being urged to rotate by means of one or more springs, weights, magnets, solenoids or other means attached to or associated with the free ends of said levers. The keys comprise pins or studs mounted in bosses formed in said slide the keys being provided with flat faces so as to allow the actuating member to reciprocate freely in the slide when the keys are in their inoperative position. When, however, the keys are rotated by means of the bell crank levers under the action of the aforesaid spring or the like the keys engage with a part of the actuating member and thereby lock the latter with said slide so as positively to actuate the movable pressure memher.

In order that the said invention may be clearly understood and readily carried into effect the same will now be more fully described with reference to the accompanying drawings which illustrate the invention as applied by way of example to a known form of box staying machine and in which:-

Figure 1' is a front elevation of the safety device according to the invention and applied to the aforesaid box staying machine showing the Figure 3 is a side elevation of the machine according to Figure 1;

Figure 4 is a section on an enlarged scale of the keys in their inoperative position;

Figure 5 is a view similar to Figure 4 showing the keys in their operative position; and v Figure 6 is a View similar to Figures 4 and 5 showing the position of the keys in which obstruction of the movable pressure member or die has occurred.

Referring now more particularly to Figures 1-3 of the drawings the movable pressure member, die or punch '7 is arranged to be reciprocated above the anvil or stationary die 8 of the machine. The movable pressure member or die 7 is carried by a slide 9 which is adapted to reciprocate in suitable slideways 10 provided upon the main frame 11 of the machine. An actuating member or block 12 is provided which is adapted to be connected to the slide 9 at the appropriate time by two keys 13, and is actuated by means of a connecting rod 14 mounted upon a pin 15 on said block and connecting the latter to a crank pin 16 rotated or carried by a driving shaft 17. The block 12 is arranged so as to reciprocate relatively to the slide 9 and to be connected thereto so as to operate the slide when the movable pressure member or die connected thereto is within a predetermined distance of the anvil, for example an eighth or three sixteenths of an inch. The actuating member or block 12 carries a threaded rod 18 having a collar 19 at its upper end between which and a diaphragm or plate 20 on the rod, a spring 21 is provided whereby the slide may be caused to operate in a resilient manner. The said rod may be rotated and a nut 22 may be provided thereon whereby the degree of pressure exerted by the aforesaid spring may be varied as desired. If desired the diaphragm or plate may be directly attached to the block or actuating member so that the pressure member 7 acts without the intermediary of the said spring 21. The keys 13 are mounted in bosses 23 upon the slide 9 and carry at their projecting ends bell crank levers 24. The keys preferably comprise transverse pins or studs having flat faces 25 so as to permit free reciprocation of the operating member or block relatively to the slide. The lower ends of the bell crank levers are preferably provided with rollers 26 which contact with a pair of guiding or cam-like surfaces 27 attached to a stationary part of the machine frame. The upper ends of the bell crank levers are actuated by means of a spring 28 which is connected to the ends of the levers whereby the spring normally urges the rollers into contact with the said sur faces the arrangement being such that the spring rotates the keys 13 into the position shown in Figure 5 when the lower ends of the levers are permitted to move apart due to the configuration of said cam surfaces. In place of the aforesaid spring, weights or other suitable means may be provided. The movement of the bell crank levers 24 may be limited by the provision of suitable stops 29 on the slide which as shown co-operate with lugs 30 or other projections on said levers. The lower edges 31 of the diaphragm or plate 20 provided upon the rod carried by the operating member or block are of arcuate form so that when the studs or pins 13 are rotated through the medium of the bell crank levers the arcuate surface of thepins project into the path of the plate or diaphragm and are engaged thereby. The plate or diaphragm is arranged so as to engage projections or shoulders 32 on the walls of the slide 9 so as to lift the slide out of contact with the anvil or stationary die upon the upward stroke of the machine. 7

During the normal operation of the machine the actuating member or bl ck 12 upon its upwardstroke serves to lift the said slide 9 as aforesaid carrying with it the two bell crank levers 24 which ride upon the cam-like surfaces 27 and rotate the said keys out of the path of the actuating' member as shown in Figure 4. On the downward stroke the slide falls by gravity and if desired against the action of a spring until such time as the bell crank levers cause the rotation of said keys by virtue of the cam-like surfaces thereby causing the actuating member or block to be positively locked to the slide as shown in Figure 5, the arrangement being preferably such that the bell crank levers rotate the keys when the movable pressure member or die is within an eighth or three sixteenths of an inch of the anvil. Should, however, obstruction occiir such as if the machine attendants finger or hand lies in thev path of the movable pressure member or die the latter is restrained in its movement with the result that the bell crank levers are not per mitted to cause rotation of the keys so that the actuating member or block reciprocates idly in the slide (Figure 6) until such time as the obstruction is removed.

It will thus be appreciated that an effective safetydevice is provided which is adapted to come into operation immediately any obstruction occurs on the movable pressure member or die. Furthermore, it will be evident that should for any reason the spring connecting the ends of the bell crank levers fail to operate, the levers will remain stationary thus the positive operation of the removable pressure member or die will be rendered ineffective.

What I claim and desire to secure by Letters Patent of the United States is:-

1. A safety device for presses, punching machines, box staying machines or the like, comprising: astationary pressure-member, a movable pressure-member for cooperation with said tionary pressure member, a slide carrying said movable pressure-member, an actuating member mounted for reciprocation in said slide, a key in said slide, a lever mounted on said key and movable with said slide, a guidin surface for engagement by said lever, a spring attached to the end of said lever, and means for reciprocating said actuating member, said guiding surface being disposed and shaped so as to permit the spring to rotate said lever, said lever being adapted to rotate said key about its longitudinal axis into the path of the actuating member to couple the actuating member to said slide so as positively to drive the movable pressure member, only when themovable pressure-member is within a predetermined distance of the stationary member.

2. A safety device for presses, punching machines, box staying machines or the like, comprising a stationary pressure-member, a movable pressure-member for co-operation with said stationary member, a slide carrying said movable pressure-member, an actuating member mounted for reciprocation in said slide, means including a pin mounted in said slide, a fiat face on said to permit the actuating member freely to reciprocate in saidslide, an operating instrumental!- ity on said pin and movable with said. slide, a guiding surface for engagement by said instrumentality on said pin, means for urging the said pin into the path of the actuatingmember, means for reciprocating said actuating member, said guiding surface being disposed and shaped soas to permit the means urging the pin to rotate said pin about its longitudinal axis into the path of the actuating member to couple the actuating member to said slide so as positively to drive the movable pressure member, only when the movable pressure-member is within a predetermined distance of the stationary member.

3. A safety device for presses,. punchingv ma.- chines, box staying machines or the like, comprising a stationary pressure-member, a movable pressure-member for cooperation with said stationary pressure member, a slide carryingv said pressure-member, an actuating member mounted for reciprocation insaid slide, a pair of pins rotatably mounted in said slide, flat faces on said pins to permit the actuating member freely to reciprocate in said slide, levers mounted onv said pins and movable with said slide,.guiding surfaces for engagement by said levers, a spring connecting-the ends of said levers, and means for reciprocating said actuating member, said' guiding surfaces being disposed and shaped so as. to permit the spring to rotate said levers, and thereby rotate said pins about their longitudinal axes into the path of the actuating member to couple the actuating member to said slide so. as positively to drive the movable pressure member, only when the movable pressure-member withwithin a predetermined distance of the stationary member.

4. A safety device for presses, punching machines, box staying machines or the like as in claim 3, wherein stops are provided on said slide and in proximity to said levers for limiting the movement of said levers.

5. A safety device for presses punching machines, box staying machines or the like comprising a stationary pressure member, a movable bell}? disposed and shaped soas to permit the spring to rotate said levers to rotate said keys its 6. A safety device for presses, punching machines, box staying machines or the like as in claim 5, wherein stops are provided on said slide and in proximity to said levers for limiting the movement thereof.

WM. L. MACFIE. 

